~~ Jo: alt text ends at metal category pie chart ~~ Cedar: figure out if document will knit ~~ Cedar: remove duplicate code chunks/rename code chunks

Library and Data Read-In

Introduction

The Environmental Protection Agency’s database of Toxic Release Inventory lacks consistency in its observations and variables – though this is due to the unexplained environment that informs the data.

Every year, new chemicals to be reported to the EPA are added to the TRI’s list, which means the amount of chemical variables within this one decade of 2011-2021 goes from 513 reported chemicals to 545 reported chemicals which actually accounts for around 200 additions and many undocumented deletions of variables (not counting the 16 that were added to the dataset in 2011). Rules on what qualifies as the threshold for reporting also change as certain chemicals fall in and out of especially-close watch. Countrywide and statewide laws on environmental protection grant even more opportunity for data to drastically change year by year, though in technicality, the actual happenings at these facilities may not be changing much at all. Some of these laws – though not implying causation – will be clarified where relevant in the code.

Our goal is to use what data we find (that is reasonably accurate given the circumstances) in order to identify the layout of these waste chemicals across the United States. To reach this, we must ask some guiding questions: What are the relationships between differing industry sectors and their growing or declining locations? Are there any shifts in the levels of overall pollution during the past decade, and are these changes set in any specific part of the country? Finally, how has chemical use and waste (as well as waste procedures) changed in the past decade, and what do we know about these chemicals from the EPA to infer their threat to human health?

Data Overview

Location Analysis

Our first question of locations deals with the trends of facilities’ presence, whether or not they are on tribal land, and their proximity to each other (possibly by industry sector) – which may help in assessing what is in the best interest of the people due to identifying the patterns of popularity at the same time as keeping safety and land protection a priority.

Number of Facilities Owned by Each Company

The five most common parent companies are as follows: U.S. Department of Defense, CRH Americas Inc, Cemex Inc, Argos U.S. Corp, and Berkshire Hathaway Inc. The first listed is a government agency responsible for U.S. military protection, followed by four different building/construction/transport materials companies.

## # A tibble: 7,925 × 3
## # Groups:   standard_parent_co_name [5,483]
##    standard_parent_co_name       parent_co_name             number_of_facilities
##    <chr>                         <chr>                                     <int>
##  1 <NA>                          <NA>                                       6433
##  2 US DEPARTMENT OF DEFENSE      US DEPARTMENT OF DEFENSE                    324
##  3 CRH AMERICAS INC              CRH AMERICAS INC                            252
##  4 CEMEX INC                     CEMEX INC                                   208
##  5 ARGOS USA CORP                ARGOS USA CORP                              186
##  6 BERKSHIRE HATHAWAY INC        BERKSHIRE HATHAWAY INC                      186
##  7 CLEAN HARBORS INC             CLEAN HARBORS INC                           136
##  8 KOCH INDUSTRIES INC           KOCH INDUSTRIES INC                         121
##  9 MARTIN MARIETTA MATERIALS INC MARTIN MARIETTA MATERIALS…                  118
## 10 TYSON FOODS INC               TYSON FOODS INC                             110
## # ℹ 7,915 more rows

~~ add code for number of facilities per state

Map of Facilities

The large majority of facilities in this dataset are located in North America, but a significant number of U.S.-owned facilities are strewn across the global map in other territories – possibly shifting any inferences that can be made on the state of pollution solely in the U.S.

Percent of Facilities on Tribal Land

Though the percentage of facilities located on tribal land is less than 1% (there are sum(facility_location$tribal_yes_no == "YES") facilities on tribal land), and we are curious about any differences in the amount of chemicals used and released on tribal vs not tribal land.

## # A tibble: 2 × 2
##   tribal_yes_no   percent
##   <chr>             <dbl>
## 1 Not Tribal Land  99.7  
## 2 Tribal Land       0.311
## # A tibble: 2 × 2
## # Groups:   tribal_yes_no [2]
##   tribal_yes_no       n
##   <chr>           <int>
## 1 Not Tribal Land 30469
## 2 Tribal Land        95

Using these tables, we have set up a groundwork map for placing chemical usage, which leads us to ask: knowing the drastic difference in percent of facilities on tribal land or not, does the location of tribal land have any effect on the type and amount of chemical release when compared to facilities not on tribal land?

We can take points from history and U.S. law, knowing that tribes of the American West often do have significant health hazards due to the many power plants, factories, mines, waste dumps, and testing sites that are placed on their land – sometimes with permission as a means to acquiring much-needed funds, and sometimes out of a tribe’s power. This question will appear further in visualizations.

Industry Analysis

Within these observations of location, there is the question of each facility’s purpose. Condensing the purpose of a factory into just 11 categories, their individual patterns of location, chemical use, and pollution can be tracked. This prevalence allows us to ask: is there a correlation between an industry’s sector and their frequency of chemicals? Further, their frequency of specific types of chemicals – carcinogens, PFAS’, and PBT’?

Industry Sector Distribution

The most common purpose of a U.S. facility is dealing with the production, waste, and wholesales of chemicals, accounting for almost 30% of U.S. industries as shown in the table. The least common accounting for about 0.4% is textile production which makes sense given trends in American imports.

## # A tibble: 11 × 2
##    industry_sector_category        percent
##    <chr>                             <dbl>
##  1 Chemicals and Waste              29.2  
##  2 Processed Materials              26.1  
##  3 Petroleum                        11.8  
##  4 Machinery and Technology         10.5  
##  5 Electric Utilities                5.81 
##  6 Wood and Paper                    5.71 
##  7 Agriculture and Food Processing   4.81 
##  8 Misc                              2.79 
##  9 <NA>                              1.80 
## 10 Mining                            1.00 
## 11 Textiles and Leather              0.400

A bar plot visualizes the distribution of industry sector categories in the Toxic Release Inventory (TRI). The plot displays the count of different industry sectors, with each bar representing a specific category. Chemical waste is the most prevalent sector, and textiles the least.

Carcinogen Percentage by Industry Sector Graph

Understandably fitting with the most common industry sector, the chemical-producing facilities (and processed materials) also use the most carcinogens (non-comprehensive), but the frequency seems to almost consistently grow with the prevalence of these sectors besides the food industry. That being said, every sector listed has a chemical usage that is majority non-carcinogenic.

A bar plot illustrates the distribution of carcinogen use across various industry sectors. Each bar represents an industry sector's prevalence, differentiated by the presence or absence of carcinogens, denoted by different fill colors. Every category uses mostly non-carcinogens, with the highest amount of carcinogens used in chemical and processing industries.

Chemical Analysis

Honing our observational questions down to just chemical trends of use and disposal now, we see how the laws of the EPA inform chemical procedures. Specifically in terms of the Clean Air Act, is there a differing correlation between the location and frequency of these specially-listed chemicals when compared to chemicals not listed on the Clean Air Act? And more broadly, is there any type, category, or closely-watched category of chemical that is most common despite the efforts of these laws?

~~ add table with number of chemicals tracked each year (maybe also graph)

The most commonly used chemical is lead, accounting for over 5% of use, followed by its compounds that make up almost 4% of use. Lead is known to cause poisoning of the human body, leading to neurological and reproductive health issues as well as impaired function of the kidneys and other body systems. Poisoning can be acquired through contaminated dust particles and products, contaminated drinking water, and contaminated soil.

## # A tibble: 627 × 2
##    chemical                                       percent
##    <chr>                                            <dbl>
##  1 Zinc compounds                                 0.00145
##  2 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) 0.00123
##  3 1,1,1,2-Tetrachloroethane                      0.00123
##  4 1,1,1-Trichloroethane                          0.00123
##  5 1,1,2,2-Tetrachloroethane                      0.00123
##  6 1,1,2-Trichloroethane                          0.00123
##  7 1,1-Dichloro-1-fluoroethane (HCFC-141b)        0.00123
##  8 1,1-Dimethylhydrazine                          0.00123
##  9 1,2,3-Trichloropropane                         0.00123
## 10 1,2,4-Trichlorobenzene                         0.00123
## # ℹ 617 more rows

Chemical Category Calculations

~~ why are these separate from the corresponding graphs????

The large majority of chemicals used are not elemental metals or metals in general. About 63% are identified in the Clean Air Act, leaving 37% not present. Over 28% of chemicals used in these facilities are known to be carcinogenic, 17% are PBTs, and 0.02% are PFAS’. These smaller percentages are still a concern, and are in-part new variables to track. PFAS did not have to be reported to the TRI until 2020 (making this decade of data insufficient), even though over 2,000 facilities were known to be producing them before the regulation. Therefore, it has far fewer observations in comparison to other chemicals though used since the 1940s and known to cause certain cancers, impairment of the immune system, reproductive issues, and abnormal developmental effects. The reporting threshold for that particular subset of chemicals is 100 pounds per year.

## # A tibble: 2 × 2
##   elemental_metal_included percent
##   <chr>                      <dbl>
## 1 NO                       0.624  
## 2 YES                      0.00737
## # A tibble: 2 × 2
##   pbt   percent
##   <chr>   <dbl>
## 1 NO       82.8
## 2 YES      17.2
## # A tibble: 2 × 2
##   pfas   percent
##   <chr>    <dbl>
## 1 NO    100.    
## 2 YES     0.0203

Chemical Categories Graphs

A grouped bar plot displays the prevalence of elemental metals used in U.S. facilities categorized by year from 2011 to 2021. Each bar represents the count of elemental metals with distinct colors indicating whether the chemicals used are or are not elemental metals. The large majority are not elemental metals, but the amount of elemental metals counted has been increasing slightly by year.

## # A tibble: 2 × 2
##   clean_air_act_chemical percent
##   <chr>                    <dbl>
## 1 NO                       0.343
## 2 YES                      0.288

A grouped bar plot displays the prevalence of Clean Air Act chemicals used in U.S. facilities categorized by year from 2011 to 2021. Each bar represents the count of chemicals with distinct colors indicating whether they are or are not identified in the Clean Air Act. The large majority are in the act, but the amount of non-act chemicals counted has been increasing slightly by year.

## # A tibble: 2 × 2
##   metal percent
##   <chr>   <dbl>
## 1 NO     0.587 
## 2 YES    0.0438

A grouped bar plot displays the prevalence of metals used in U.S. facilities categorized by year from 2011 to 2021. Each bar represents the count of metals with distinct colors indicating whether the chemicals used are or are not metals. Most of them are not metals, and the amount of metals and non-metals counted has been increasing by year. 

## # A tibble: 6 × 2
##   metal_category                                   percent
##   <chr>                                              <dbl>
## 1 Non_Metal                                        0.528  
## 2 Individually-listed compounds that contain metal 0.0434 
## 3 Metal complound categories                       0.0282 
## 4 Elemental metals                                 0.0184 
## 5 May contain metal                                0.00848
## 6 Metals with qualifiers                           0.00491

A faceted bar plot depicts the prevalence of metal categories used by U.S. facilities from 2011 to 2021, whether a non-metal, metal with qualifiers, metal compound, chemical possibly containing metal, indivudually-listed metal compound, or elemental metal. Each bar represents the count of these metal categories, sorted by year, with varied colors denoting distinct metal category types.

A grouped bar plot shows the prevalence of carcinogens used in U.S. facilities categorized by year from 2011 to 2021. Each bar represents the count of carcinogenic substances, sorted by year, with varied colors indicating different carcinogen categories. The majority of chemicals used are non-carcinogenic.

A grouped bar plot shows the prevalence of PBTs used in U.S. facilities categorized by year from 2011 to 2021. Each bar represents the count of PBT substances, sorted by year, with different colors indicating whether a chemical is or is not a PBT. The large majority of chemicals used are non-PBTs, with the number of PBTs being relatively consistent by year.

A grouped bar plot shows the prevalence of PFAS chemicals used in U.S. facilities categorized by year from 2011 to 2021. Each bar represents the count of PFAS substances, sorted by year, with different colors indicating whether a chemical is or is not a PFAS. The overarching majority of chemicals used are not PFAS, and PFAS data only appears for the years 2020 and 2021.

For above visualizations: elemental metals (some harmless, some causing neurotoxicity) keep a near-consistent distribution in the chemical data. The few increases this type of metal makes in the data is adjusted by the many additions of tracked chemicals in the dataframe, also causing the count for non-elemental-metals to increase. A similar state of increase goes for the amount of Clean Air Act chemicals and their growing amendments (still with more Clean Air Act chemicals than not) and with the general metals graph (more non-metals than metals, though both counts increasing). The amount of PBTs remains consistent with the non-PBTs increasing with new variables, and our two years of PFAS data show their consistency – though, of course, not much judgement can be made through this small piece of information, and the same must go for much of these environmentally-altered graphs.

Metal Category Pie Chart

A circular pie chart demonstrates the distribution of metal categories used by U.S. facilities in the dataset. Each segment of the pie represents a metal category with distinct colors, with the size proportional to the percentage of occurances. Non-metals make up 54% of the chart, and elemental metals make up 19% of the chart.

For above visualizations: elemental metals (some harmless, some causing neurotoxicity) keep a near-consistent distribution in the chemical data. The few increases this type of metal makes in the data is adjusted by the many additions of tracked chemicals in the dataframe, also causing the count for non-elemental-metals to increase. A similar state of increase goes for the amount of Clean Air Act chemicals and their growing amendments (still with more Clean Air Act chemicals than not) and with the general metals graph (more non-metals than metals, though both counts increasing). The amount of PBTs remains consistent with the non-PBTs increasing with new variables, and our two years of PFAS data show their consistency – though, of course, not much judgement can be made through this small piece of information, and the same must go for much of these environmentally-altered graphs.

Chemical Categories

There are 1857 carcinogens being observed – a large number creating a small percentage.

## # A tibble: 1,857 × 2
## # Groups:   chemical [187]
##    chemical                  carcinogen
##    <chr>                     <chr>     
##  1 1,1,1,2-Tetrachloroethane YES       
##  2 1,1,1,2-Tetrachloroethane YES       
##  3 1,1,1,2-Tetrachloroethane YES       
##  4 1,1,1,2-Tetrachloroethane YES       
##  5 1,1,1,2-Tetrachloroethane YES       
##  6 1,1,1,2-Tetrachloroethane YES       
##  7 1,1,1,2-Tetrachloroethane YES       
##  8 1,1,1,2-Tetrachloroethane YES       
##  9 1,1,1,2-Tetrachloroethane YES       
## 10 1,1,1,2-Tetrachloroethane YES       
## # ℹ 1,847 more rows

There are 3797 non-carcinogens being observed.

## # A tibble: 3,797 × 2
## # Groups:   chemical [440]
##    chemical                                       carcinogen
##    <chr>                                          <chr>     
##  1 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO        
##  2 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO        
##  3 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO        
##  4 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO        
##  5 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO        
##  6 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO        
##  7 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO        
##  8 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO        
##  9 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO        
## 10 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO        
## # ℹ 3,787 more rows

There are sum(chemical_info$pfas == "YES") observations of PFAS chemicals in the dataset.

## # A tibble: 88 × 2
## # Groups:   chemical [56]
##    chemical                                                                pfas 
##    <chr>                                                                   <chr>
##  1 1,1,2,2-Tetrahydroperfluorodecyl acrylate                               YES  
##  2 1,1,2,2-Tetrahydroperfluorododecyl acrylate                             YES  
##  3 1,1,2,2-Tetrahydroperfluorohexadecyl acrylate                           YES  
##  4 1,1,2,2-Tetrahydroperfluorotetradecyl acrylate                          YES  
##  5 1-Decanol, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluoro-        YES  
##  6 1-Octanesulfonamide, 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro… YES  
##  7 1-Octanesulfonamide, 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro… YES  
##  8 1-Octanesulfonamide, N-butyl-1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptade… YES  
##  9 1-Propanaminium, 2-hydroxy-N,N,N-trimethyl-, 3-[(γ-ω-perfluoro-C6-20-a… YES  
## 10 1-Propanaminium, 2-hydroxy-N,N,N-trimethyl-, 3-[(γ-ω-perfluoro-C6-20-a… YES  
## # ℹ 78 more rows

There are sum(chemical_info$pfas == "NO") observations of non-PFAS chemicals in the dataset.

## # A tibble: 5,566 × 2
## # Groups:   chemical [571]
##    chemical                                       pfas 
##    <chr>                                          <chr>
##  1 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  2 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  3 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  4 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  5 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  6 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  7 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  8 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  9 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
## 10 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
## # ℹ 5,556 more rows

There are sum(chemical_info$pbt == "YES") observations of PBT chemicals in the dataset.

## # A tibble: 233 × 2
## # Groups:   chemical [23]
##    chemical pbt  
##    <chr>    <chr>
##  1 Aldrin   YES  
##  2 Aldrin   YES  
##  3 Aldrin   YES  
##  4 Aldrin   YES  
##  5 Aldrin   YES  
##  6 Aldrin   YES  
##  7 Aldrin   YES  
##  8 Aldrin   YES  
##  9 Aldrin   YES  
## 10 Aldrin   YES  
## # ℹ 223 more rows

There are sum(chemical_info$pbt == "NO") observations of non-PBT chemicals in the dataset.

## # A tibble: 5,421 × 2
## # Groups:   chemical [604]
##    chemical                                       pbt  
##    <chr>                                          <chr>
##  1 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  2 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  3 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  4 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  5 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  6 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  7 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  8 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
##  9 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
## 10 1,1,1,2-Tetrachloro-2-fluoroethane (HCFC-121a) NO   
## # ℹ 5,411 more rows

Pollution analysis

From these distributions of observed chemicals, there is still the question of their disposal after use. With air, ground, and water being some possible points of disposal, we must assess the trends in these differing types of waste removal. In the past decade, what are these trends in pollution due to chemical release, whether on-site or off?

On-Site Pollution by Category

By Type

On-site release types: variables Underground, Landfill, and Surface Impoundment are all zero.

A smoothed scatter plot visualizes the relationship between fugitive air releases and on-site release totals of chemicals used in U.S. facilities from 2011 to 2021. Each point represents a data observation, and most years show a steep decline in fugitive air release with larger on-site release.

A smoothed scatter plot visualizes the relationship between stack air releases and on-site release totals of chemicals used in U.S. facilities from 2011 to 2021. Each point represents a data observation, and most years show a steep decline in stack air release with larger on-site release.

A smoothed scatter plot visualizes the relationship between water releases and on-site release totals of chemicals used in U.S. facilities from 2011 to 2021. Each point represents a data observation, and most years show a steep decline in water release with larger on-site release.

A smoothed scatter plot visualizes the relationship between underground (Class 1) releases and on-site release totals of chemicals used in U.S. facilities from 2011 to 2021. Each point represents a data observation, and most years show a steep decline in underground (Class 1) release with larger on-site release.

A smoothed scatter plot visualizes the relationship between underground (Class 2-5) releases and on-site release totals of chemicals used in U.S. facilities from 2011 to 2021. Each point represents a data observation, and most years show a consistently straight line of underground (Class 2-5) release even with larger on-site release.

A smoothed scatter plot visualizes the relationship between land treatment and on-site release totals of chemicals used in U.S. facilities from 2011 to 2021. Each point represents a data observation, and most years show a small decline in land treatment with larger on-site release.

A smoothed scatter plot visualizes the relationship between other disposal and on-site release totals of chemicals used in U.S. facilities from 2011 to 2021. Each point represents a data observation, and all years show a steep increase in other release with larger on-site release.

By Year

Pollution by General Category (Including On-site-total)

Pollution variable Releases is all zeros.

Detailed Analysis

Chemicals and Location

## # A tibble: 11 × 2
##    chemical                         n
##    <chr>                        <int>
##  1 Lead                         47031
##  2 Nickel                       28432
##  3 Chromium                     27333
##  4 Ammonia                      25778
##  5 Styrene                      13327
##  6 Benzo[g,h,i]perylene         13248
##  7 Formaldehyde                  8093
##  8 Mercury                       4418
##  9 Chloroform                     971
## 10 Arsenic                        616
## 11 Phosphorus (yellow or white)   432
## # A tibble: 11 × 6
## # Groups:   chemical [11]
##    chemical                  pfas  pbt   clean_air_act_chemical carcinogen     n
##    <chr>                     <chr> <chr> <chr>                  <chr>      <int>
##  1 Lead                      NO    YES   NO                     YES        47031
##  2 Nickel                    NO    NO    YES                    YES        28432
##  3 Chromium                  NO    NO    YES                    NO         27333
##  4 Ammonia                   NO    NO    NO                     NO         25778
##  5 Styrene                   NO    NO    YES                    YES        13327
##  6 Benzo[g,h,i]perylene      NO    YES   YES                    NO         13248
##  7 Formaldehyde              NO    NO    YES                    YES         8093
##  8 Mercury                   NO    YES   YES                    NO          4418
##  9 Chloroform                NO    NO    YES                    YES          971
## 10 Arsenic                   NO    NO    YES                    YES          616
## 11 Phosphorus (yellow or wh… NO    NO    YES                    NO           432
## # A tibble: 14,994 × 4
## # Groups:   standard_parent_co_name, parent_co_name [4,654]
##    standard_parent_co_name parent_co_name      facility_name number_of_chemicals
##    <chr>                   <chr>               <chr>                       <int>
##  1 CLEAN HARBORS INC       CLEAN HARBORS INC   CLEAN HARBOR…                  11
##  2 CLEAN HARBORS INC       CLEAN HARBORS INC   CLEAN HARBOR…                  11
##  3 DOW INC                 DOW INC             THE DOW CHEM…                  11
##  4 CLEAN HARBORS INC       CLEAN HARBORS INC   CLEAN HARBOR…                  10
##  5 CLEAN HARBORS INC       CLEAN HARBORS INC   CLEAN HARBOR…                  10
##  6 WASTE MANAGEMENT INC    WASTE MANAGEMENT I… CHEMICAL WAS…                  10
##  7 OLIN CORP               OLIN CORP           BLUE CUBE OP…                   9
##  8 <NA>                    CENOVUS ENERGY INC. LIMA REFININ…                   9
##  9 <NA>                    REPUBLIC SERVICES … US ECOLOGY N…                   9
## 10 <NA>                    TRADEBE GP          TRADEBE TREA…                   9
## # ℹ 14,984 more rows

## # A tibble: 21 × 3
##    chemical             tribal_yes_no       n
##    <chr>                <chr>           <int>
##  1 Ammonia              Not Tribal Land 25706
##  2 Ammonia              Tribal Land        72
##  3 Arsenic              Not Tribal Land   611
##  4 Arsenic              Tribal Land         5
##  5 Benzo[g,h,i]perylene Not Tribal Land 13170
##  6 Benzo[g,h,i]perylene Tribal Land        78
##  7 Chloroform           Not Tribal Land   960
##  8 Chloroform           Tribal Land        11
##  9 Chromium             Not Tribal Land 27202
## 10 Chromium             Tribal Land       131
## # ℹ 11 more rows

## # A tibble: 56 × 2
##    state chemical_use
##    <chr>        <int>
##  1 AL              11
##  2 AR              11
##  3 AZ              11
##  4 CA              11
##  5 CO              11
##  6 FL              11
##  7 GA              11
##  8 IA              11
##  9 IL              11
## 10 IN              11
## # ℹ 46 more rows

Overview graphs

Chemical Release Graphs

Graphs of on-site release by type

Graphs of on-site disposal by type

Graphs of off-site disposal by type

Conclusion

In recognizing the increase of observations, increase in pollution trends, and the environment of increasingly strict reporting laws, we must be careful not to make the assumption that pollution is truly on the rise, and that conditions are getting worse in general. What the legal environment shows is an increase in control and recognition of needed chemical regulations. What the work shows is a very actively polluted environment irregardless of these laws, and the continued prevalence of chemicals that are known to have been used as weapons of war and for body-preservation and alteration – clearly harmful to human health. This is not to say that there is no improvement, but that there surely is much more that must be done.